筒阀两种动水关闭方式下水力特性分析

Analysis on Hydraulic Characteristics of Ring Gate in Two Kinds of Emergency Shut-down Processes

为了更加全面分析混流式水轮机飞逸退出过程的水力特性,以水轮机的全流道为计算控制域,运用RNG k-湍流模型、动网格和滑移网格技术,对筒阀60和26 s两种动水关闭方式进行了三维非定常流动数值模拟,对比分析了两种动水关闭方式下阀体周边的压力、速度等流场的流态分布状况,以及筒阀附近包括蜗壳、导叶、转轮等在内的过流部件的流场特征。计算结果表明,与60 s动水关闭方式相比26s动水关闭方式明显缩短了飞逸时间,有利于操作的稳定性,可以更好地降低飞逸现象对水轮机组造成的破坏。同时,对于研究更为合理的筒阀运动方式、水轮机的水力设计与优化都具有一定的参考价值。

To study the hydraulic characteristics of the Francis hydraulic turbine in its runaway quit process more comprehensively,the three-dimensional unsteady numerical simulation was made on the 60 s and 26 s shut-down processes,the computational control domain was the whole passage in hydraulic turbine.The RNG k-turbulence models,dynamic mesh and sliding mesh were adopted in the simulation,further detail comparative analyses were made on the two emergency shut-down methods including the pressure and velocity distribution on the flow field around the ring gate,as well as the flow field characteristics of the diversion components such as the spiral case,guide vanes and the runner.The results show that the 26 s shut-down method spends less time than the 60 s shut-down method in the runaway process,which is in favor of operation stability,as well as bringing down the damage caused by the runaway phenomenon more effectively.The results also have some reference value for both researching more reasonable motion method of the ring gate and the hydraulic design and optimizing of the hydraulic turbine in the future.